This invention generally relates to power converters, and more specifically, to switching power supplies in integrated circuits.
Typical server processors require six to eight distinct voltage levels (e.g. core, I/O, memory, etc.) at the chip level. This drives complexity in the first level package, and consumes space for multiple DC-DC converters as well as additional power plane wiring levels in the system board. Further, while most of the voltage levels are between 1 and 2 Volts (with the exception of I/O drivers), the current levels are high enough to cause significant resistive losses as well as electromigration lifetime issues in (medium to high power) chip solder C4s which are used to join the chip to the first level package. In particular, such challenges limit the number of independent, high-current voltages that can be delivered to a chip, which becomes problematic as it restricts the ability to perform fine-grain voltage control within a chip (e.g. independent voltage islands to create separate voltages per processor core) to improve power efficiency.